Firing mechanism



June 17, 194-1. w, SU 2,245,621

FIRING MECHANISM Filed May 22, 1939 3 Sheets-Sheet l 1,, 4 Att v ney5- June 17, 1941. w, SUMMERBELL 1 2,245,621

FIRING MECHANISM Filed May 22, 1939 3 Sheets-Sheet 2 Willi mElummE-w El J2 At'tn'r' E 5 June 17, 1941. w, SUMMERBELL 2,245,621

FIRING MECHANISM Filed May 22, 1959 3 Sheets-Sheet 3 Patented June 17, 1941 FIRING MECHANISM William Summerbell, Watervliet, N. Y., assignor to Government of the United States of America, as represented by the Secretary of War and his successors in office Application May 22, 1939, Serial No. 274,985

I (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 9 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The'subject of this invention is a firing mechanism.

The purpose .of the invention is to provide a firing'mechanism in which the firing pin spring is inoperated to enable the firing pin to complete its movement to firing position through its own inertia and to have a corresponding unrestrained retraction to permit opening of a transversely movable breech'block. While these purposes have been generally accomplished in mechanisms as shown in U. S. Patent No. 1,750,722 intended for guns of larger caliber the present structure'is particularly designed for rapid firing guns of smaller caliber) The invention is characterized by a novel provision for self-retraction. by a cooking lever which permits manual actuation and by a transversely movable sear which can be moved out of engagement by a trigger that is operable only when the breech block is closed.

The specific nature of the invention as well as other'objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a view of a breech mechanism partly in plan and partly in'section on the line ll of Fig. 2 v 7 1 Fig. 2 is a sectional view on the line 2- -2 of Fig. 1 showing the breech block in elevation;

Fig. 3 is a View in side elevation and partly in section of the firing pin;

Fig. 4 is an enlarged sectional viewon the line l-l of Fig. 2 and showing the firing mechanism in self-retracted position;

Fig. 5 is a similar view with the'firing mechanism in cocked position;

Figs. 6 and 7 are detail sectional views of elements of the firing mechanism;

Fig. 8 is a view in front elevation of the elements of Figs. 6 and 7 in assembled position;

Fig. 9 is a fragmentary view in left side'elevation of the breech ring;

Fig. 10 is a detail'sectional view l0l0 of Fig. 9;

Fig. 11 is a plan View of the cap;

Figs. 12 and 13 are views respectively in plan and rear elevation of the sear.

Referring to the drawings by characters of reference there is shown a breech ring A having an opening for a vertically sliding breech block on' the line B, the mechanism for operating the block being omitted. The breech block is formed with a bore 6 (Figs. 4 and 5) which is closed at the face of the block by a plug 7 having an aperture 8.

The firing mechanism which is housed in the bore 6 comprises a sleeve 9, a stop collar ID, a spring H and a firing pin unit consisting of a guide I2, a holder l3 and firing pin M.

The guide I2 is a cylindrical member slidable in the bore 6 and having a lug 15 on its right side movable in a slot IS in the block and a cam lug I? on its lower side movable in a slot H3 in the block and serving to restrain the guide against rotational displacement. The front closed end 19 (Figs. 7 and 8) of the guideis centrally apertured to fixedly receive the collar I la of the firing pin. The firing pin is threaded in the holder, and the collar I ia abuts an annular shoulder l9a in the end !9.

The opposite sides of the front end of the guide are'cut away to the thickness of the end l9 to provide openings 20 for a pair of forwardly extending fingers 2I-2I formed on the stop collar l0 and arranged to engage the plug 1. The collar l0 provided with a central opening for the holder I3, is slidably mounted within the guide l2 and adapted to be moved into contact with the inner surface of the end 19 by the spring II.

The rear end of the holder I3 is formed with a head 22 which is slidable within the sleeve 9. The sleeve has an inturned flange 23 at its front end for engaging the forward face of the head 22 whileat its rear end it has an outwardly turned flange 24 to form a seat for the spring I I.

The sleeve 9 is slidable within and confined by a cap 25 (Figs. 4 and 11) including a tubular guide 26 which is inserted in and closes the bore 6. The cap is provided on opposite sides with a pair of similar lugs 27-4! each having its rear corners cut away as at 28 and each having in its rear face, a semi-cylindrical recess 29 in extension of an aperture 30. A pin 3! fixed in the upper part of the breechblock depends into the bore 6 and serves to engage in the recess 29 and the rim of aperture 30 and hold the cap in place. Assembly is accomplished by moving the cap into the bore until it engages the annular shoulder 32, imparting a quarter turn to position the recess 29 in line with the pin 3!, and then allowing the spring II to urge the cap rearwardly and efiect locking engagement. This procedure is reversed when it is desired to remove the cap and the firing mechanism.

The lug l5 extending laterally from the guide I2 is arranged to be engaged by the offset lower arm 33 of a cocking lever 34 (Figs. 1 and 2) which is mounted on the breech block by means of a pivot pin 35. The upper extremity of the cocking lever extends above the breech ring A so that it may be manually actuated with the breech block B in closed position. Normally the cocking lever is adapted to be initially rotated during lowering of the breech block by engagement with the breech ring and it is provided with a lug 36 which rides over a pin 31 carried by the breech ring to provide for the final rotation. The inner end of pin 31 extends into a slot 31a in the breech block. A plunger 38 acts on the lower arm 33 to normally maintain the lower arm in the forward position.

During lowering of the block the cooking lever retracts the guide I2 and firing pin and holder to the position shown in Fig. 5, thereby compressing the spring ll. During this retraction the cam lug l1 moves the sear 39 (Fig. 13) laterally against the action of sear spring 40. When the lug IT clears the sear, the latter is restored by its spring to be interposed in the path of the lug l1 and in this manner the sear holds the firing mechanism in cocked position.

A trigger 4! (Figs. 9 and rotatably mounted in the breech ring includes a tripper 42 which engages a cam 43 on the sear 39 to move the sear laterally of the block and out of engagement with the lug H on the guide l2. The means for actuating the trigger is illustrated as a rod 44 which is mounted on a non-recoiling gun carriage in a known manner.

The trigger 42 has a depending arm 45 with an inwardly directed finger 46 extending across the front face of the breech block. When the block is closed preparatory to firing, the actuation of the trigger to disengage the sear moves the finger 46 into a recess 41 in the front face of the block. The finger is cammed out of this recess when the block is lowered. In any other position of the block the finger is restrained by the front face of the block so that this provision positively prevents movement of the trigger to fire the gun except when the breech block is closed. A plunger 48 is provided for normally moving the trigger to the non-firing position.

When the firing mechanism is in the cooked position as seen in Fig. 5. the spring II is compressed and the sleeve 9 is seated against the cap 26. When the sear is disengaged through actuation of the trigger, the spring I I acts through the collar to drive the guide and firing pin forward (Fig. 4) The fingers 2| on engaging the plug 1 arrest the forward motion of the collar but the firing pin, under the influence of inertia, continues forwardly to strike the primer of a cartridge C. During this movement the head 22 of the firing pin holder acting on the inturned flange 23 of the sleeve 9 moves the sleeve forwardly to further compress the spring II. The spring, in recovering, immediately moves the sleeve rearwardly against the cap and the flange 24 by virtue of its engagement with the head 22, retracts the firing pin to a position within the plug so that it will not interfere with opening of the breech block. The further retraction of the guide by the cooking lever has been previously described.

I claim:

1. In a firing mechanism, a breech block having a bore, a hollow guide slidable within the bore and having an apertured front end, a firing pin carried by the front end and having a rear portion with a head disposed within the guide, a collar slidable within the guide and on the firing pin and having fingers projecting forwardly through the front end of the guide to engage the breech block, a sleeve slidable within the bore and having an outwardly turned flange on its rear end and an inwardly turned flange on its front end engageable with the front face of the head on the firing pin, a spring confined between the collar and the rear flange of the sleeve, and means for confining the rear end of the sleeve.

2. In a firing mechanism, a breech block having a bore, a hollow guide slidable within the bore and having an apertured front end, a firing pin carried by the front end and having a rear portion with a head disposed within the guide, a collar slidable within the guide and on the firing pin and having fingers projecting forwardly through the front end of the guide to engage the breech block, a sleeve slidable within the bore and having means for engaging the front face of the head of the firing pin, a spring confined between the collar and the sleeve, means for confining the rear end of the sleeve, and means for retracting the hollow guide to cock the firing pin.

3. In a firing mechanism, a breech block having a bore, a hollow guide slidable within the bore and having an apertured front end, a firing pin carried by the apertured front end of the guide and extending on opposite sides of said front end, a collar slidable within the guide and having fingers projecting through the front end of the guide, a sleeve slidable within the bore and having mutually actuating engagement with the firing pin, a spring confined between the collar and the sleeve, means for confining the rear end of the sleeve, and means for retracting the hollow guide to cock the firing pin.

4. In a firing mechanism, a breech block, a firing pin member slidable in the breech block, a front spring seat collar engageable with the firing pin member, means for limiting forward movement of the collar short of the firing pin member, a rear spring seat member having mutually actuating engagement with the firing pin member, a spring confined between the rear spring seat member and the front spring seat'collar, means for confining the rear end of the rear spring seat member, and means for retracting the hollow guide to cock the firing pin.

5. In a gun, a breech ring, a vertically sliding breech block in the breech ring, a firing pin in the breech block, a cocking'lever pivotally mounted in the breech block above the firing pin and extending above the breech ring to be in position formanual actuation, said cocking lever having means engageable with the breech ring on lowering of the breech block whereby it is rotated to retract the firing pin.

6. In a gun, a breech ring, a vertically sliding breech block in the breech ring, a firing pin in the breech block, a cocking lever pivotally mounted in the breech block above the firing pin and having means engageable with the breech ring on lowering of the breech block whereby it is rotated to retract the firing pin.

'7. In a gun, a breech ring, a vertically sliding breech block in the breech ring, a firing pin in the breech block, a firing pin having a cam lug, means for cooking the firing pin, a sear slidable transversely in the breech block and arranged to be moved by the cam lug'on the firing pin, a sear spring for moving the sear into the path of movement of the cam lug, a trigger carand engageable with the breech block to main- 10 tain the trigger in such rotated position.

9. In a breech block having a bore for a firing mechanism, a pin carried by the block and extending into the bore, a member for closing the bore, a lug on said member having a, recess in its rear face engageable with the pin on turning the closing member, and a firing mechanism spring acting to normally hold the lug against the pin.

WILLIAM SUMMERBELL. 

